The term “adjustment element” should be understood here in broad terms. It comprises, for example, a tailgate, a rear cover, an engine hood, a side door, a luggage compartment flap, a rising roof or the like of a motor vehicle.
The known linear drive (DE 20 2011 109 569 U1), on which the invention is based, is configured as a spindle drive. It serves for the motorized adjustment of a motor vehicle adjustment element configured as a tailgate.
The known linear drive has a drive train with a drive motor for generating a driving force between two coupling points which each comprise a joint part. The joint parts of the linear drive have a bearing portion configured as a ball socket, a joining part arranged thereon and a connecting portion arranged thereon which is furthermore in engagement with the linear drive. A connecting portion is in engagement with one end of a guide tube which is connected at its other end to a spindle nut.
The mechanical stability of the joint part, in particular the stability of the engagement between the connecting portion and the guide tube, obtains particular importance in the case of the known linear drive in so far as a helical spring is provided which pushes the two coupling points of the linear drive apart under high pretensioning. In the event of a breakage of the joint part, in particular in the event of release of the engagement between the connecting portion and the guide tube, an abrupt movement apart of the two coupling points occurs. This undesirable operation can scarcely be controlled and entails corresponding destruction and injury risks, and therefore the configuration of bearing portion, joining part and connecting portion from steel has proven successful. However, this is associated with high material and production costs and with a relatively high component weight.